<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <button id="btn">提交</button>
    <script>
      const btn = document.getElementById("btn");
      btn.onclick = function (e) {
        // 事件对象
        console.log(e);
      };
      // 行为
      // btn.onclick();
    </script>
  </body>
</html>
